1. Field of the Invention
This invention relates, in general, to a fluid delivery system for delivering samples to a chromatographic column and methods for their use.
2. Description of Related Art
A number of different techniques have heretofore been employed for delivering liquid samples to chromatographic columns. Such techniques employ a hollow needle which draws fluid into a syringe through a filter. The sample is thereafter delivered to the column.
Existing systems for delivering liquid samples typically use a single filter composed of a microporous material or membrane. An exemplar of a conventional filter is U.S. Pat. No. 5,567,309 to Classon et al. which shows a filter having a filter cap with a thin membrane covering an opening on the bottom of the cap. The thin membrane is formed of a microporous element housed in a filter receptacle and has a porosity between 0.1 and 1 microns. The filter may include a multiple layer construction formed of multiple, different, thin membrane layers. The filter membrane(s) are thin to allow for a higher flow rate through the filter. As such, the Classon system sacrifices filtering capacity. Moreover, because Classon makes use of a thin filter, the filter is likely to become clogged and obstructed more often which leads to increased downtime.
There is also a need to provide a system which more efficiently accesses liquid sample from a plurality of sample holding vials. Conventional techniques lack automation and require a user to identify a vial and control the system to access the identified vial.
In light of the foregoing, it would be beneficial to have methods and apparatuses which overcome the above and other disadvantages. It would be desirable to provide a system with higher-efficiency filtering performance. It would be desirable to provide a system with less downtime for filter cleaning and replacement.
It would be desirable to provide a system with greater efficiency for accessing and delivery fluid samples.